For a number of years it has been the practice to employ equipment to deposit artificially made snow on outdoor surfaces, such as ski slopes, when nature does not provide the desired quantity of snow. A variety of mechanical devices have been employed.. Generally, the approach is to take water droplets and convert them to frozen particles. Prior art devices typically break up a stream of water by means of pressure atomizing and or two-fluid (air-water) atomizing. Often fans are used to provide an airstream which entrains the droplets as they become frozen, and better to carry them through space and deposit them across a wide area.
There are various problems and limitations connected with prior art snow making devices. They include complexity, noise, reliability, weight, difficult maneuverability, low efficiency in covering a desired area, poor ability for making snow at comparatively warm temperatures, high initial cost, and high operating cost. Of the various factors, there are three upon which the present invention is intended to improve, as follows.
First, there is often a tendency for the snow makers to freeze up or become coated with ice from the water being atomized, especially in severe cold and certain wind conditions. In other instances debris clogs fine nozzles. Thus, users, want reliability in the sense that the snowmaker can be depended upon to make snow without frequent operator intervention, to remove ice buildup or unclog nozzles.
Second, a snowmaking system ought have low operating and maintenance costs. Since many snowmakers use compressed air, as does the present invention, good use must be made of such air, since the cost of operating and maintaining compressors is a major factor. So, the air/water ratio ought be minimized.
Third, snowmakers ought be able to make snow when ambient conditions are near to the freezing point of water and relative humidity (wet bulb temperature) is high. It is comparatively easy to make snow when the temperature and humidity are low, for instance when the dry bulb and wet bulb temperatures are less than 20.degree. F. However, when temperatures are "high"--in the 20-32.degree. F. range, many snowmakers will undesirably deposit on a slope a fine coating of ice, slush or water, because the water droplets insufficiently freeze as they are carried through the air toward the earth. Thus, especially when ski slopes are not located in inherently colder regions, ski slope operator income can be substantially affected by the ability to make good amounts of snow in marginal (high) temperature and humidity conditions..
Several commercial snowmakers make snow by atomizing water with compressed air to form fine frozen particles, or nuclei. The fine ice particles are combined with separately formed streams of water droplets which comprise the preponderance of the water flow through the snowmaker. The fine particles act as nuclei since they cause the droplets to freeze and drop to the earth as artificial snow. In their absence, the droplets by themselves typically will not readily freeze before falling to earth.. The parts of the apparatus which generate the frozen particles, called the nucleator, tend to be prone to inherent freezing, and sometimes electric heaters are provided to avoid such. However, when the snowmaker does not have a fan, requiring a heater necessitates additional complication and cost in providing the unit with electricity.
While there are snowmakers which have superior performance at the high ambient temperatures, they also tend to be the most complex and costly. Some high performance snow makers generate fine droplet sprays by using fine orifices. But unfortunately, the water supplies used in the field often have solid particulate and dirt, and careful filtering (and resultant maintenance) is required, elsewise clogging or inferior performance results. The present invention seeks to improve on the limitations of the prior art snowmakers.
The foregoing and other objects, features and advantages of the invention will become more apparent from the following description of preferred embodiments and accompanying drawings.